Light signal



March 22, 1938. w. B. WELLS ET AL 2,111,650.

LIGHT S IGNAL Filed July 9, 1936 3 Sheets-Sheet l fi M l)- 1.9 1.9 I

Fig.1.

INVENTQRS LUerlegBll/ellr and w- BY THEIR ATTORNEY March 22, 1938.- w. B. WELLS ET AL LIGHT S IGNAL Filed July 9, 1936 5 Sheets-Sheet 2 INVENTORS ll/esZeyBlI/ellr and lgggle'a THEIR ATTORN EY March 22, 1938. w, WELL H M 2,111,650

I LIGHT SIGNAL Filed July 9, 1936 3 Sheets-Sheet 3 1N1IENTbR$ lI/eyley B. ll/ellr' and willie! .Loclihapf; BY

THEIR ATTORNEY Patented Mar. 22,1938

' UNITED: STATES PATENT OFFICE;

LIGHT SIGNAL Wesley B. Wells, Wilkinsburg, and William K. Lockhart, Penn Township, Pa., assignors to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application, July 9, 1936, Serial No. 89,852

3 Claims. (01. 177-329) 'Our invention relates to light signals, and para gasket of felt or the like being interposed beticularly to light signals which are capable of tween the ring member and the edges of this lens; selectively projecting a plurality of beams of The two lenses 9 and I are of the'well-known light of different colors from a single light source. piano-convex type, and are both clear or colorless.

We will describe one form of light signal em- Secured to the outer end of the lens barrel dibodying our invention, and will then point out the rectly above the outer lens in is a hood l8 which novel features thereof in claims, performs the usual function of shielding the lens In the accompanying drawings,- Fig. 1 is a II! from the direct rays of the sun. vertical sectional view showing one form of light Mounted in a vertical position between the two signal embodying our invention. Fig. 2 is a rear lenses 9 and III by means of two spring clips 20, 10

elevational view of the signal shown in Fig. 1, a which are secured at their lower ends to the lens portion of the door being broken away to better barrel, as best seen in Fig. 3, is a prismatic screen illustrate'the construction of the parts. Fig. 3 IS, the inner face of which is provided with a i is a detail sectional view of a portion of the signal plurality of horizontally disposed prisms I9 The shown in Figs. 1 and 2 taken on the line III-III prisms l9 are so designed as to project a portion 15 of Fig. 1. Fig. 4 is a side view of the light unit A of the light rays from the light unit A upwardly and associated supporting bracket 45 forming part and to spread them vertically, as indicated by the of the signal illustrated in Figs. 1 and 2. dash lines 52. The signal when constructed in Similar reference characters refer to similar the manner shown is intended for use as a parts in each of the several views. dwarf signal, that is to say, a signal which is 20 Referring first to Figs. 1 and 2, the light signal disposed below the level of an engine cab, and in the form here shown comprises a box-like the upwardly deflected rays provide an indication casing I provided with a hinged rear door 2 to an observer close to the signal, as will be through which convenient access to the entire readily understood. 7 inside of the casing may be had. The door 2 is To facilitate cleaning the inner lens 9 and the arranged to be fastened in its closed position by prismatic screen IS, the underside of the signal 25 means of a suitable fastening device 3, and is barrel is provided with a hand-hole 2| which is provided on its inner face with a groove 4 for closed by a removable cover 22 held in place by a the reception of packing 5, which, when the door pair of thumb screws 23, only one screw 23 being 1 is closed, engages the edges of the casing I, and visible in the drawings. The portion of the casthus seals the casing against the entry of dirt or ing around the hole 2| is provided with a dependother foreign substances. ing annular flange 24, and interposed between the Formed in the forward wall i of the casing I cover 22 and this flange is a gasket 25 of cork or is a large circular opening I through whichthe the like, which gasket seals the lens barrel against light rays from a light'unit A which is disposed the entry of dirt, moisture or the like. 35

inside of the casing are adapted to beprojected, The light unit A referred to hereinbefore comand secured to the forward wall i directly in prises an ellipsoidal reflector 30 mounted in an front of the opening I by means of four screws insulating casing 3|, and an electric lamp 82, the 8 spaced 90 apart is a lens unit L for concenfilament of which is located at the focal point of trating the light rays emitted by the light unit A the reflector 30. The casing 3| is preferably con- 40 into a signal beam. The lens unit L is of wellstructed of an insulating material which can be 7 known construction, and comprises a doublet conreadily molded, such, for example, as a phenol sisting of two spaced lenses 9 and I0 mounted in condensation product, and comprises two parts 3| the inner and outer ends, respectively, of a tubuand 3| secured together by means of bolts 32 lar casing ll, commonly referred to as a lens passing through aligned lugs 33. The reflector 45 barrel. The outer lens It bears around its edges is held in place in the casing 3| by means of an against the bottom of'an annular groove l2 which inwardly extending annular flange 34 which is is formed in the lens barrel, and is held inplace formed on the forward end of the part 3|, and by a ring member I3 and screws It, a gasket of by a ring member 35. The flange 34 engages the felt or' the like being preferably interposed bereflector at its forward edge, while the ring mem- 50 tween the ring member and the edges of the lens. ber 35 surrounds the rear portion of the reflector The inner lens 9 likewise bears at its edges against and abuts against an annular shoulder 36 which is the bottom of an 'annular groove l5 which is formed on the part 3|. A felt band 31 is interformed in the inner end of the lens barrel and is posed between the ring member and the reflector held in place by a ring member l6 and screws II, to prevent damage to the reflector by the ring member. The'rear wall of the part 3| oi the casing 3| is provided with four rearwardly projecting studs 31 arranged in rectangular formation, and mounted on these studs between compressed coil springs 38 which surround the fiange portions of the studs, and nuts 39 which are ad-' justably screwed onto the outer ends of the studs, is a plate 40. This plate carries a socket 4| which projects with some clearance through a hole 42 formed in the rear wall of the part 3| of the casing 3|, andserves as a support for the previously referred to electric lamp 82. It will be apparent that by adjusting the nuts 39 the position of the lamp filament with respect to the reflector may be varied, and these nuts are so adjusted that the filament of the lamp will be located at the exact focal point of the reflector; thus enabling the maximum efficiency to be obtained from the light unit.

The light unit A is mounted in a triangula supporting bracket 45 in a manner which we will describe shortly, and the bracket 45, in turn, is adjustably secured by means of three adjustable fastening devices 4'6, 41, and 48,. to three lugs 49, 59, and 5|, which project inwardly from the top and two sides, respectively, of the casing The fastening devices 46, 41, and 48 are similar, and a description of one will therefore suffice for all. Referring to the fastening device 46, for example, this fastening device comprises a threaded sleeve 46 which is adjustably screwed through a tapped hole 52 formed in the bracket 45, and a fillister head screw 46 which extends with some clearance through the sleeve 46' and is screwed at its inner end into a tapped hole 54 provided in the lug 49. The sleeve 46- is provided at its outer end with a hexagonal flange or wrench grip 45 to facilitate turning the sleeve, and has mounted thereon a lock nut 46 for locking,the sleeve in an adjusted position. The inner end of the sleeve 46 is machined fiat. and the surface of the lug 49 against which the sleeve bears is also machined fiat. Furthermore, the surface of the lug 49 against which the sleeve 46 bears is machined so that it lies in the same vertical plane as the corresponding surfaces of the lugs and 5|, and all three machined surfaces bear a fixed relation to the lens unit L of the signal.

In adjusting the fastening device 46, the lock nut 46 is backed off to unlock the sleeve 46, and the screw 46 is then backed out far enough to permit the sleeve 4'6 to be rotated. The sleeve 46 is then rotated to the desired position and locked in place by again tightening the lock nut 46*, after which the screw 46 is again tightened. The three adjustable fastening devices 46, 41, and 48 are so adjusted that the conjugate focal point 43 of the light unit A will coincide exactly with the focal point of the doublet combination, as indicated by dash lines 52. This adjustment is made in a dark room at the factory during the process of manufacture of the signal, and after this adjustment has once been made the sleeves are then permanently locked in place by means of the associated lock nuts 46. The advantage of this arrangement is that if it subsequently becomes desirable to remove the light unit and bracket assembly as a whole from the signal case, as may sometimes happen, for reasons which will appear hereinafter, this can be done by merely removing the screws 46 41 and 48 of the fastening devices, and when the unit and bracket are subsequently replaced and the screws 46, 41 and 48 are again tightened the location of the conjugate focal point 43 of the light unit will again coincide, with the focal point of the lens unit.

In addition to being able to at times remove t' light unit and bracket assembly as a whole from the signal, it is also desirable to be able to readily remove the light unit from the bracket 45 to enable the lamp'82 to be replaced when it burns out, and to facilitate cleaning the inner surface of the reflector 30. To this end, the bracket 45 is provided with a hole 45 which receives the forward end of the casing of the light unit with a sliding fit, and with a boss 45 around the hole 45* having an accurately machined vertically disposed surface 45. The surface 45 of the boss 45 cooperates with the forward surfaces 55' and 56 of two semi-circular projections 55 and 56, which are molded on the part 3| of the casing 3| of the light unit A, in such manner that when the surfaces 55 and 56 are engaging the surface 45, the axis of the light unit will extend at right angles to the plane of the supporting bracket. The projections 55 and 56 are spaced from each other at their ends (see Figs. 2 and 4) and one end of each projection is formed with an integral latch catch 55 or 56, which is adapted to cooperate with two latch springs 51 and 58 that are secured to the rear surface of the supporting bracket 45. The parts are so proportioned that if the light unit is pushed into the hole 45 in either one of two angular positions spaced 180" apart, to the position in which the surfaces 55 and 56* engage the surface 45 of the boss 45", the spring clips will enter the spaces between the ends of the projections 55 and 56, and that, if the unit is then rotated through a slight angle in a clockwise direction, as viewed in Fig. 2, the latch springs will pass over humps which form parts of the latch catches and will drop into notches which also form parts of the latch catches, thereby locking the light unit in a fixed position with respect to the supporting plane.

The light signal also comprises a suitable operating mechanism S for changing the color of the beam emitted by the signal to provide a plurality of signal indications. As here shown, this mechanism is similar in all respects to that described in our copending application for Letters Patent of theUnited States, Serial No. 88,768, filed on July 3, 1936, for Light signals, and if a full description of this mechanism is desired, reference may be had to this copending application. Briefly described, this mechanism comprises a top plate 59 of insulating material having secured thereto a polarized electro-responsive means for operating, between an intermediate and two extreme positions, a spectacle arm 60 which projects upwardly through a slot in the top plate into an auxiliary casing 6| which is secured to the top plate. The spectacle arm 60 is provided at its upper end with green, red, and yellow color screens which align respectively with two windows 62 and 63 of clear glass according as this spectacle arm occupies its one extreme position, its intermediate position, or its other extreme position. Only the red screen 64 is shown in the drawings, but spectacle arms of the type described are well known, and it is therefore deemed to be unnecessary to show this spectacle arm in detail herein.

The mechanism S is secured to the casing by means of a supporting pin 65 which projects into a socket 66 formed in the top plate, and by means of two screws 61 and 68. The screws 61 and 68 project through upwardly extending lugs 69 formed on a strap 10 which is secured to the top plate 59, and are screwed into tapped holes formed in the lugs 50 and 5|. directly below the holes which receive the screws 41* and 48 of the fastening devices 41 and 48. It will be noted that in order to fasten the mechanism S in place it is necessary to remove the light unit A and associated bracket 45. The pin 65 extends through a hole II in the forward wall I of the casing l and is held in place by means of the lens barrel. The mechanism is so positioned with respect to the casing I that the light rays emitted by the light unit A will pass through the windows 62 and 63 of the signal mechanism and the color screen which happens to be in alignment with these windows in the manner indicated in the dash lines 52. It will be apparent, therefore, that the signal will display a green, red, or yellow aspect according as the spectacle arm 60 occupies its one extreme position, its intermediate position or its other extreme position. The top plate 59 is provided with suitable terminal posts for making connections with the operating mechanism, and for the reception of the wires through which current is supplied to the light unit. Secured to the bottom of the casing l are adjustable supporting means 12 and 13 for-moving the signal casing to different positions. The bottom of the casing is also provided with an opening 14 for the reception of a conduit 15 through which wires may be led into the signal casing. These last-named parts are all of standard'construction, and form no part of our present invention.

In some instances,- it is desirable to provide suitable means to assist in directing the signal beam toward the desired zone of observation. For

this purpose, a, sighter comprising a bracket 16 provided with two vertically extending arms 16* and 16 is secured to the upper side of the casing l by means of studs 8 l. The arms of this sighter are provided with aligned holes 16 and 16, the hole 16 being covered by a washer I18 adjustably held in place by a plate 11, said washer being provided with a peep hole 18, and the hole 16 being provided with a tube 18 having a pair of intersecting cross hairs 80 in its outer end. The washer say, a signal which is intended to be located above the level of an engine cab, by merely removing the lens unit L from the casing, rotating it through an angle of 180, and again fastening it to the casing, the parts being so constructed as to readily permit this change. When the lens unit is changed in this manner, it is necessary, of"

course, to change the position of the hood l8 so that it is again disposed above the outer lens Ill.

It should alsobe pointed out that since the casing 3| of the light unit A is constructed of insulating material, if this casing should accidentally come in contact with any of the terminal posts which are mounted on the top plate 59 during the process of removing the light unit from the supporting bracket or restoring it to its proper position in the bracket, it will not short circuitany circuits the wires of which are connected to the terminal posts.

One advantage ,of a signal constructed in accordance with our invention is that since the light unit is accurately positioned with respect to the lens unit and the filament of the light unit is accurately positioned with respect to the reflector of the light unit in the manner described, the

maximum possible signal efficiency is obtained.

Another advantage of a signal constructed in accordance with our invention isthat the light units are interchangeable, thus making it possible to quickly and conveniently replace a light'unit in case any part of it becomes unfit for use, for

any reason. a

A further advantage of a signal embodying our invention is that, due to thevarious adjustand subsequently replaced without disturbing the efficiency of the signal.

Although we have herein shown and described only one form of light signal embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. A light signal comprising a casing having adjustably secured to said casing in a predetermined position with respect to the focal point of said lens unit, a housing attached to said bracket and containing a reflector and a light source located at the focal point, of said reflector, and positioning means on the housing cooperating with the bracket for fixing the position of said reflector with respect to said casing, whereby the conjugate focal point of the reflector of any housing attached to said bracket will coincide with the focal point of said lensunit.

2. A light signal comprising a casing having an opening provided with a lens unit the focal point of which is located inside of said casing, a bracket having an opening and a machined surface suran opening provided with a lens unit, a bracket rounding said opening, a light unit comprising a a housing containing a reflector and a light source accurately positioned at the focal point of said reflector, said reflector being of the type having a conjugate focal point and said light unit being provided with a positioning surface which bears a fixed relation to the conjugate focal point of said reflector, means for removably securing said light unit in the opening in said bracket in the position in which the positioning surfaceon said light unit engages the machined surfaces on said bracket in flat surface relationship, and means for adjustably securing said bracket to said casing so adjusted that the conjugate focal point of the reflector of any light unit secured to said bracket will coincide with the focal point of said lens 3. A light signal comprising a casing having an opening, a lens unit secured to said casing in front of said opening, a bracket having a machined'surface, a light unit comprising a housing containing a reflector having a conjugate focal point and an electric lamp the filament of which is accurately positioned at the main focal point of said reflector, said housing being provided with a surface which is accurately located with respect to the conjugate focal point of said reflector, means fordetachably securing said light unit to the conjugate focal point of the reflector of the light unit when the light unit is secured to the bracket will coincide with the focal point of said lens unit, and means disposed at the focal point of the lens unit for controlli'ngthe rays of light 5 passing from said light unit to said lens unit.

WESLEY B. WELLS 

